This invention relates to a folding photovoltaic strip device.
It has already been proposed in Japanese Publication No. JP363117472A, publication date May 21, 1998, xe2x80x9cPortable Solar Bell Power Sourcexe2x80x9d, N. Yanagihara and Z. Ito, to provide a power source by winding a long, flexible, thin film solar cell onto a winding shaft and store the wound film in a package.
It has been proposed in U.S. Pat. No. 5,605,769 dated Feb. 25, 1997, xe2x80x9cMethod and apparatus for supplying electrical energy to battery powered equipmentxe2x80x9d, D. J. Toms, wherein electrical energy is supplied to, for example, a rechargeable battery by unfurling, i.e. unwinding, a flexible, light converting to electrical energy, strip of photovoltaic cells to form a flat surface for exposure to light.
While these devices are useful, there is a draw back in that,
i) if the light converting strip is bent to be coiled, to a radius less than 1 inch (2.54 cm) for storage, performance degradation of the strip in the conversion of light will possibly occur, see, for example, xe2x80x9cLightweight, Flexible, Monolithic Thinxe2x80x94Film Amorphous Silicon Modules on Continuous Polymer Substratesxe2x80x9d, D. Grimmer, F. Jeffrey, S. Martens and M. Thomas, J. Solar Energy, 1996, Vol. 18, page 210, last paragraph;
ii) a light converting strip at minimum coiling diameter of 2 inches (5.08 cm) is unduly bulky; and,
iii) bending the whole lengths of the photovoltaic cells cause bending stresses at easily damage portions of them, such as, for example, bus bars, each time the cells are coiled or uncoiled.
There is a need for a photovoltaic strip device which, when stores, is not subjected to bending damage by being furled or coiled, which is capable of being stored in a compact manner, and which need not have easily damaged portions subjected to damaging bending stresses each time the strip is coiled or uncoiled.
According to the present invention, there is provided a folding photovoltaic strip device, comprising:
a. a plurality of photovoltaic modules,
b. a support with the modules spaced therealong and adhering thereto to form a strip with exposed portions of the support between the modules, and wherein,
c. at least some of the exposed portions of the support are pleated by transversely extending flexible, permanent creases to form a series of panels wherein the creases will spring open, whereby
i. with the panels folded together in a concertina manner, by means of the creases, the device is stored in a retracted, compact form and,
ii. with the panels spread out by means of the creases being sprung open, the modules can be exposed to light that is convertible by the modules to electrical energy.
The panels may be essentially flat.
The flexible creases may be at intermediate positions across modules.
Each module may be provided with a flexible crease.
The flexible creases may be spaced at a module length apart from one another.
The flexible creases may be spaced with at least one module between each pair of them.
The device may include diode electrically connected to the device and through which an article may be electrically energized by the device.
The flexible creases are preferably permanent creases.
Preferably, the permanent creases are open creases that, in the relaxed state, expose the modules to light, and, the strip has sufficient stiffness to be compressed to the retracted, compact form.